The primary goal in the treatment of wounds is to achieve wound closure. Open cutaneous wounds represent one major category of wounds and include burn wounds, neuropathic ulcers, pressure sores, venous stasis ulcers, and diabetic ulcers. Open cutaneous wounds routinely heal by a process which comprises six major components: i) inflammation, ii) fibroblast proliferation, iii) blood vessel proliferation, iv) connective tissue synthesis v) epithelialization, and vi) wound contraction. Wound healing is impaired when these components, either individually or as a whole, do not function properly. Numerous factors can affect wound healing, including malnutrition, infection, pharmacological agents (e.g., actinomycin and steroids), diabetes, and advanced age [see Hunt and Goodson in Current Surgical Diagnosis & Treatment (Way; Appleton & Lange), pp. 86-98 (1988)].
Wounds which do not readily heal can cause the subject considerable physical, emotional, and social distress as well as great financial expense [see, e.g., Richey et al., Annals of Plastic Surgery 23(2):159-165 (1989)]. Indeed, wounds that fail to heal properly and become infected may require excision of the affected tissue. A number of treatment modalities have been developed as scientists' basic understanding of wounds and wound healing mechanisms has progressed.
The most commonly used conventional modality to assist in wound healing involves the use of wound dressings. In the 1960s, a major breakthrough in wound care occurred when it was discovered that wound healing with a moist occlusive dressings was, generally speaking, more effective than the use of dry, non-occlusive dressings [Winter, Nature 193:293-94 (1962)]. Today, numerous types of dressings are routinely used, including films (e.g., polyurethane films), hydrocolloids (hydrophilic colloidal particles bound to polyurethane foam), hydrogels (cross-linked polymers containing about at least 60% water), foams (hydrophilic or hydrophobic), calcium alginates (nonwoven composites of fibers from calcium alginate), and cellophane (cellulose with a plasticizer) [Kannon and Garrett, Dermatol. Surg. 21:583-590 (1995); Davies, Burns 10:94 (1983)]. Unfortunately, certain types of wounds (e.g., diabetic ulcers, pressure sores) and the wounds of certain subjects (e.g., recipients of exogenous corticosteroids) do not heal in a timely manner (or at all) with the use of such dressings.
Several pharmaceutical modalities have also been utilized in an attempt to improve wound healing. For example, treatment regimens involving zinc sulfate have been utilized by some practitioners. However, the efficacy of these regimens has been primarily attributed to their reversal of the effects of sub-normal serum zinc levels (e.g., decreased host resistance and altered intracellular bactericidal activity) [Riley, Am. Fam. Physician 24:107 (1981)]. While other vitamin and mineral deficiencies have also been associated with decreased wound healing (e.g., deficiencies of vitamins A, C and D; and calcium, magnesium, copper, and iron), there is no strong evidence that increasing the serum levels of these substances above their normal levels actually enhances wound healing. Thus, except in very limited circumstances, the promotion of wound healing with these agents has met with little success.
What is needed is a safe, effective, and interactive means for enhancing the healing of chronic wounds. The means should be able to be used without regard to the type of wound or the nature of the patient population to which the subject belongs.